Simplify the following expression: $a = \dfrac{-5n + 1}{7n} \div \dfrac{1}{3}$
Answer: Dividing by a number is the same as multiplying by its inverse. $a = \dfrac{-5n + 1}{7n} \times \dfrac{3}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $a = \dfrac{(-5n + 1) \times 3} {(7n) \times 1}$ $a = \dfrac{-15n + 3}{7n}$